Differentials provided with a drive wheel, especially for motor vehicles, have become well-known, for example, from U.S. Pat. No. 6,176,152. Differentials of this type are provided with one pair of differential pinions and one pair of axle bevel gears in a housing formed from two halves or parts, whereby the one housing part also has the flange for the ring gear, which generally is manufactured by forging or by forging and subsequent ring rolling, wherein the metal-cutting and the heat treatment and optionally fine machining of the gearing occurs after the forging. Afterwards, the ring gear is fastened to the flange part, e.g., welded, riveted, screwed or the like.
With respect to the prior art, this US patent specification refers to an embodiment in which the housing and the flange-like fastening area for the ring gear are a one-piece casting. Since this spherical and one-piece differential housing, which is provided with a fastening flange for the ring gear, must be manufactured by casting, it is associated with an expensive metal-cutting in connection with poor accessibility, especially to the interior areas. The assembly of the differential shaft as well as of the differential pinions and axle bevel gears on their axles and into the housing is also extremely difficult, awkward, and expensive. In addition, slide inserts are also provided between the bevel gears and the housing surfaces adjacent to the rear, which increases the aforementioned disadvantages of assembly in view of the narrow space conditions that prevail there and due to the poor accessibility.
In the apparatus of this US patent specification, the housing is constructed as two parts, whereby, however, the two housing parts are each produced by press rollers starting from a round blank, and are subsequently joined together after the chip-forming machining operations. In addition, the ring gear still has to be attached. The attachment of the ring gear results in a high labor cost, particularly since the joint surfaces on both the ring gear and on the fastening area of the flange have to be machined, and with high precision, so that the concentricity and flatness requirements for the overall assembly can be met. In this regard, if tolerances from the machining of the individual parts unfavorably coincide, they can exacerbate the assembly tolerances.